If you think about the verb “dive” too hard, it can shake your confidence that you know which past tense to use.
Let’s say you’re telling someone about a diving competition you participated in yesterday. Do you tell them you dived yesterday, or do you tell them you dove?
Not all verbs cause this sort of confusion.
Regular verbs like “play” have the same past tense and past participle – I play, I played, I have played. Irregular verbs like “drive” are a little trickier – I drive, I drove, I have driven.
For much of its life, “dive” was a regular verb – dive/dived/dived. But in the modern era, we English speakers created an irregular past tense – dove.
Why? Because sometimes we do that.
In Old English, there were two classes of regular verbs. There were verbs that take a final “d” -- what we now think of as regular verbs. There was another robust class of verbs that changed the internal vowel in order to form the past tense.
Enough verbs from that class have become “ed” verbs or have died out, that we now just think of them as irregular verbs. However, you can see traces of the system when you look at certain verbs like sing/sang/sung, ring/rang/rung, and swim/swam/swum.
As such, every once in a while we take a regular verb and decide to make it irregular by doing a vowel change – like how “drive” becomes “drove.”
Merriam-Webster says “dived” and “dove” are both acceptable, but the latter is much more common in American English, while the former is more common in British English.